(1) Field of the Invention
The present invention relates to a shielded cable assembly comprising a shielded-conductor cable and a shielded joint connected thereto.
(2) Description of the Prior Art
A conventional shielded-conductor cable comprises a set of insulated conductors and a cable shield applied over the insulated conductor set. In order to facilitate connection of the cable and another cable or an electrical apparatus, a shielded joint is mounted on a terminal end of the cable. The joint comprises a plurality of electrical contacts and a conductive shield electrically insulated from the electrical contacts. When the joint is mounted on the terminal end of the cable, the electrical contacts and the conductive shield are electrically connected to the insulated conductors and the cable shield, respectively. A combination of the cable and the joint will be referred to herein as a shielded cable assembly.
Generally speaking, an electrical signal transmitted through an electric cable comprises a plurality of frequency components over a range from a comparatively low frequency to a high frequency. During a time when the signal transmits in the cable, the signal, in particular, the high frequency components are radiated from the cable and undesirably intrude into, as noise, other electric and/or electronic apparatus disposed in the surroundings of the cable assembly.
The shielded cable assembly is useful to transmit an electrical signal between electric and/or electronic units with reduction of the undesirable radiation. This is because the insulated conductors and the contacts are covered with the cable shield and the conductive shield, respectively.
However, the cable shield must be stripped off at a connecting portion between the cable and the joint, so that the undesired radiation tends to be made from the connecting portion. Although a conventional shield joint uses a metallic shell to reduce the radiation, shield effect of the metallic shell is not so sufficient. Further, use of the metallic shell results in high cost and increased weight of the joint. It is also complex to connect the metallic shell and the cable shield.
On the other hand, it is known that the undesired radiation is effectively reduced by mounting a cylindrical magnetic member on the shielded cable adjacent the shield joint. However, it is difficult to mount such a cylindrical magnetic member onto the cable together with the shield joint.